You have several switches configured in a switch stack configuration. You want to make the EtherChannel resilient to failure. Which feature should you use?

A. OSPF
B. PAgP
C. Cross-stack EtherChannel
D. EtherChannel load-balancing

C. Cross-stack EtherChannel allows you to configure EtherChannels between physical switches to act as one EtherChannel. If one switch or SPF transceiver goes bad, the rest of the switching will be supported by the other physical switches.